Gas Chromatography (GC) is an analytical technique used to separate, identify, and quantify volatile compounds in a mixture.
Principle:
GC works on the principle of differential distribution of components between a stationary phase and a mobile phase:
- Compounds that interact less with the stationary phase move faster through the column.
- Compounds that interact more with the stationary phase move slower.
- This difference in travel time (retention time) allows the separation of components.
Components of Gas Chromatography:
- Mobile Phase:
- An inert gas such as helium, nitrogen, or hydrogen that carries the sample through the column.
- Stationary Phase:
- A liquid or solid coating inside a column, often a polymer, that interacts with the sample molecules.
- Injector:
- Introduces the sample into the gas stream.
- Column:
- Where separation occurs based on differences in volatility and interaction with the stationary phase.
- Detector:
- Detects and records the separated components as peaks on a chromatogram.
Applications:
- Analysis of gases, volatile liquids, and essential oils.
- Detection of environmental pollutants.
- Forensic and toxicological analysis.
- Quality control in pharmaceuticals and food industry.
In short, gas chromatography separates volatile substances in a mixture based on their interaction with a stationary phase and their boiling points, allowing identification and quantification.